To Sleep, Perchance to Dream: Crash Course Psychology #9

Summary

Comedian Mike Birbiglia's sleep mishap introduces the complex world of sleep and dreams. The script delves into the stages of sleep, from NREM to REM, and the benefits of slumber for physical and mental health. It explores various sleep disorders and theories on the purpose of dreaming, from Freud's wish-fulfillment to cognitive development, highlighting the ongoing scientific inquiry into the mysteries of our unconscious mind.

Takeaways

• 😴 Sleep is a complex state of consciousness that is not fully understood, with science still exploring its depths.
• 🛌 Mike Birbiglia's sleep-related accident highlights the active nature of the brain during sleep, contrary to the common belief that it goes dormant.
• 🧠 Sleep is essential for health and survival, with potential functions including recuperation, growth hormone release, and mental function support.
• 👶 The discovery of REM (Rapid Eye Movement) sleep by Eugene Aserinsky revolutionized sleep research, revealing high brain activity during sleep.
• 🌀 The sleep cycle consists of four distinct stages: NREM 1, 2, 3, and REM, each with unique brainwave patterns.
• 🚫 Lack of sleep can lead to serious health issues, including depression, weight gain, and immune system suppression.
• 🤔 Various sleep disorders, such as insomnia, narcolepsy, sleep apnea, and REM sleep behavior disorder, can significantly impact quality of life.
• 😱 Night terrors and sleepwalking occur during deep NREM sleep and are distinct from nightmares, which happen during REM sleep.
• 🤯 Dreams are a mix of daily experiences, emotions, and memories, and their purpose is still debated among scientists.
• 🧐 Theories about the purpose of dreams include wish-fulfillment, information processing, physiological function, cognitive development, and neural activity models.

Q & A

What unusual incident involving Mike Birbiglia is described in the script?

Mike Birbiglia experienced a sleep disorder where he dreamt a guided missile was coming towards him, causing him to jump out of a hotel window, which he also did in reality, resulting in 33 stitches and a visit to a sleep specialist.

What is the significance of sleep in terms of our brain's activity?

Sleep is another state of consciousness where the brain remains active, contrary to the common belief that it simply goes dormant. It's a time when the brain processes the day's events, supports growth through hormone release, and is essential for memory and creativity.

What discovery did Eugene Aserinsky make about sleep that changed scientific understanding?

Eugene Aserinsky discovered the REM (Rapid Eye Movement) stage of sleep, proving that the brain does not simply 'power down' during sleep but instead exhibits significant activity, even while the body is in deep slumber.

How many distinct stages of sleep do humans experience, and what are they?

Humans experience four distinct stages of sleep: NREM-1, NREM-2, NREM-3, and REM sleep. Each stage is defined by unique brainwave patterns and levels of consciousness.

What is the function of melatonin in relation to sleep?

Melatonin, released by the pineal gland at night, is a hormone that helps induce sleep by signaling to the body that it is time to wind down and rest.

What is the paradoxical aspect of REM sleep?

The paradox of REM sleep is that while the brain is highly active, the body, particularly the muscles, is in a state of temporary paralysis, except for the eyes which move rapidly.

How often does the sleep cycle, including REM sleep, typically repeat itself?

The sleep cycle, including all stages of NREM and REM sleep, typically repeats itself every 90 minutes or so.

What are some of the negative health impacts of sleep deprivation?

Sleep deprivation can lead to a weakened immune system, slowed reaction times, an increased risk of depression, weight gain due to hormonal imbalances, and can affect mood and mental abilities.

What is narcolepsy and how does it affect its sufferers?

Narcolepsy is a sleep disorder where individuals experience sudden and uncontrollable attacks of overwhelming sleepiness, which can disrupt daily activities and potentially be dangerous, such as while driving or performing other tasks requiring alertness.

What are night terrors and how do they differ from nightmares?

Night terrors are episodes of screaming, thrashing, and increased heart and breathing rates that occur during sleep, typically in children under seven, and are often not remembered upon waking. They occur during the NREM-3 stage of sleep, unlike nightmares, which happen during REM sleep and can be recalled.

What are some theories about the purpose of dreaming?

Theories about the purpose of dreaming include wish-fulfillment (Freud), information processing, physiological function, cognitive development, and the idea that dreams are accidental side-effects of the brain trying to make sense of random neural activity during REM sleep.

Outlines

00:00

😴 The Importance and Mysteries of Sleep

Comedian Mike Birbiglia's sleep-related accident highlights the complex nature of sleep, which is more than just a dormant state. Sleep is a state of consciousness with significant health implications. Despite its importance, the scientific community still debates the exact reasons for sleep, though it is linked to recuperation, growth, and mental function. The script introduces the audience to the history and technology of sleep research, starting with the discovery of REM sleep by Eugene Aserinsky. It outlines the four stages of sleep—NREM 1, 2, 3, and REM—and the physiological changes that occur during each stage. The script also touches on the health risks of sleep deprivation and various sleep disorders, emphasizing the need for further understanding and research.

05:01

🌙 Sleep Disorders and the Science of Dreams

This section delves into specific sleep disorders such as insomnia, narcolepsy, sleep apnea, and REM sleep behavior disorder, which Mike Birbiglia was diagnosed with. It discusses the potential causes of these disorders, including neurotransmitter deficiencies and physical conditions. The script then explores the phenomenon of night terrors and differentiates them from nightmares, explaining their occurrence during different sleep stages. The focus then shifts to the nature of dreams, their vividness, and their potential psychological functions. It introduces various theories about the purpose of dreaming, including wish-fulfillment, information processing, physiological function, cognitive development, and neural activity models. The section concludes by emphasizing the ongoing debate and research into the functions of dreams and REM sleep.

10:01

🎬 Behind the Scenes of Crash Course: Sleep

The final paragraph provides credits and acknowledgments for the production of the video. It thanks the viewers, especially the Subbable subscribers who support the channel. It invites potential sponsors to participate in the show's funding and offers incentives like special decals and the opportunity to be animated into an episode. The paragraph lists the writing, editing, and consulting team behind the episode, including Kathleen Yale, Blake de Pastino, and Dr. Ranjit Bhagwat. It also credits the director and editor, Nicholas Jenkins, the script supervisor and sound designer, Michael Aranda, and the graphics team from Thought Café, showcasing the collaborative effort involved in creating the educational content.

Keywords

💡Sleep

Sleep is a periodic, natural, and reversible state of near-total unconsciousness. The video emphasizes that sleep is far from a dormant period for the brain or body, as it plays a vital role in physical recovery, memory consolidation, and mental function. For example, sleep supports neuron repair and releases growth hormones.

💡REM Sleep

REM (Rapid Eye Movement) sleep is a sleep stage characterized by heightened brain activity and vivid dreaming. Despite the brain's activity, the body remains in a state of paralysis except for the eyes, which move rapidly. The discovery of REM sleep by Eugene Aserinsky challenged the idea that the brain 'powers down' during sleep and is central to understanding dreams.

💡NREM Sleep

Non-Rapid Eye Movement (NREM) sleep encompasses three stages, from light to deep sleep, each with distinct brainwave patterns. In NREM-3, delta waves dominate, marking the deepest sleep phase, which is crucial for physical restoration. This stage is also when phenomena like sleepwalking and night terrors occur.

💡Hypnagogic Sensations

Hypnagogic sensations are brief, often startling experiences that occur as a person is falling asleep. They can include a sudden feeling of falling or muscle jerks. In the video, they are mentioned as part of the transition into NREM-1 sleep, when the brain's alpha waves start slowing down.

💡Sleep Disorders

Sleep disorders are medical conditions that interfere with normal sleep patterns, such as insomnia, narcolepsy, sleep apnea, and REM sleep behavior disorder. The video highlights Mike Birbiglia's experience with REM sleep behavior disorder, where he physically acted out his dreams, leading to injuries.

💡Dreams

Dreams are vivid, emotional experiences that occur primarily during REM sleep. They often reflect daily activities, emotional states, or abstract scenarios. The video explores various theories about why we dream, such as Freud’s wish-fulfillment theory and modern cognitive development and information processing models.

💡Neural Activity

Neural activity refers to the electrical signals generated by neurons in the brain. The video discusses how sleep, particularly REM sleep, stimulates neural activity, helping maintain and develop neural pathways. This is crucial for memory consolidation, learning, and brain development, especially in infants.

💡Sleep Spindles

Sleep spindles are bursts of rapid brainwave activity that occur during NREM-2 sleep. They indicate that a person is in a light but definite sleep stage, where they can still be easily awakened. These spindles play a role in memory consolidation and overall brain function during sleep.

💡Sleep Deprivation

Sleep deprivation occurs when a person consistently lacks sufficient sleep, leading to negative effects on mental and physical health. The video explains that sleep deprivation can impair cognitive functions, increase the risk of depression, weaken the immune system, and affect weight regulation through hormonal imbalances.

💡Oneirology

Oneirology is the scientific study of dreams. The term is derived from the Greek word 'oneiros,' meaning dream. The video discusses how oneirology combines neuroscience and psychology to explore the purpose and nature of dreams, including their cognitive and physiological functions.

Highlights

Comedian Mike Birbiglia experienced a sleep disorder that led to a dramatic incident involving a hotel window.

Sleep is a state of consciousness, not just a time of dormancy for the brain or body.

Science has made significant strides in understanding why we sleep and what occurs in the brain during sleep.

Sleep is essential for health and survival, with potential benefits including cell repair and growth hormone release.

Eugene Aserinsky's discovery of REM sleep challenged the notion that the brain powers down during sleep.

There are four distinct stages of sleep, each with unique brainwave patterns.

REM sleep is paradoxical, with high brain activity despite muscle paralysis, except for eye movements.

Sleep deprivation can lead to health issues, including depression, weight gain, and immune system suppression.

Various sleep disorders, such as insomnia and narcolepsy, can severely impact quality of life.

Mike Birbiglia was diagnosed with REM sleep behavior disorder, associated with a dopamine deficiency.

Night terrors and sleepwalking occur during deep NREM sleep and are distinct from nightmares.

Dreams are a complex phenomenon, with theories suggesting they serve purposes from wish-fulfillment to cognitive development.

The information processing theory posits that dreams help consolidate memories and process daily experiences.

Physiological function theory suggests that dreaming may promote neural development and preserve neural pathways.

Cognitive development theory proposes that dreams engage brain networks similar to those used in daydreaming and reality processing.

Neural activity models propose that dreams might be accidental byproducts of the brain's attempt to make sense of random neural firings during REM sleep.

The episode concludes with a teaser for the next topic: altered states of consciousness, including the effects of drugs and hypnosis.

Transcripts

Comedian Mike Birbiglia was having trouble with sleep.

Though not with the actual sleeping part -- one night, while staying in a hotel, he dreamed

that a guided missile was on its way to his bed, and in his dream, he jumped out the window

to escape it.

Unfortunately, he also did this not in his dream.

From the second floor.

And the window was not open.

This little episode cost him 33 stitches and a trip to a sleep specialist.

Mike now sleeps in zipped-up mummy bags for his own safety.

The lesson here?

Sleep is not some break time when your brain, or your body, just goes dormant.

Far from it.

In truth, sleep is just another state of consciousness.

And only in the past few decades have we begun to really plumb its depths -- from why we

sleep in the first place, to what goes on in our brains when we do, to what happens

when we can’t sleep.

And there is a lot that science has to say about your dreams!

Talk about weird!

It’s like Sigmund Freud meets Neil Gaiman.

So, even though it may seem like you’re dead to the world, when you sleep, your perceptual

window remains slightly open.

And kinda like Mike Birbiglia’s hotel room window, a trip through it can make for a pretty

wild ride.

But for your safety and enjoyment, I’m here to guide you through this state of consciousness,

where you’ll learn more than a few things about human mind, including your own.

And here’s hoping you won’t need any stitches when we’re through.

[INTRO]

Technically speaking, sleep is a periodic, natural, reversible and near total loss of

consciousness, meaning it’s different than hibernation, being in a coma, or in say, an

anesthetic oblivion.

Although we spend about a third of our lives sleeping, and we know that it’s essential

to our health and survival, there still isn’t a scientific consensus for why we do it.

Part of it probably has to do with simple recuperation, allowing our neurons and other

cells to rest and repair themselves.

Sleep also supports growth, because that’s when our pituitary glands release growth hormones,

which is why babies sleep all the time.

Plus, sleep has all kinds of benefits for mental function, like improving memory, giving

our brains time to process the events of the day, and boosting our creativity.

But even if we’re not quite sure of all the reasons why we sleep, technology has given

us great insight into how we sleep.

And for that we can thank little Armond Aserinsky.

One night in early 1950s Chicago, eight-year-old Armond was tucked into his bed by his father.

But this night, instead of getting a kiss on the forehead, little Armond got some electrodes

taped to his face.

Armond’s dad was Eugene Aserinsky, a grad student looking to test out a new electroencephalograph,

or EEG machine, that measures the brain’s electrical activity.

That night, as his son slept peacefully, he watched the machine go bonkers with brain

wave patterns, and -- after making sure that his machine wasn’t somehow broken -- discovered

that the brain doesn’t just "power down" during sleep, as most scientists thought.

Instead, he had discovered the sleep stage we now call REM or rapid eye movement, a perplexing

period when the sleeping brain is buzzing with activity, even though the body is in

a deep slumber.

Aserinsky and his colleague Nathaniel Kleitman went on to become pioneers of sleep research.

Since then, sleep specialists armed with similar technology have shown that we experience four

distinct stages of sleep, each defined by unique brainwave patterns.

Say you’re just going to bed.

All day your endocrine system has been releasing “awake” hormones like cortisol.

But with nightfall comes the release of sleepy melatonin hormones from the pineal gland.

Your brain is relaxed, but still awake, a level of activity that EEGs measure as alpha

waves.

You’re feeling sleepy, your breath slows, and suddenly you’re asleep.

This exact moment is clearly evident on an EEG reading, as those alpha waves immediately

transition to the irregular non-Rapid Eye Movement stage one (NREM-1) waves.

It’s in this first stage of sleep you might experience hypnagogic sensations -- those

brief moments when you feel like you’re falling, and your body jerks, startling you.

As you relax more deeply, you move into NREM-2 stage sleep, as your brain starts exhibiting

bursts of rapid brain wave activity called sleep spindles.

You’re now definitely asleep, but you could still be easily awakened.

NREM-3 comes with slow rolling delta waves.

We now know that you can have brief and fragmentary dreams in the first three stages of sleep,

but eventually you’ll get to the most important stage: full REM sleep, that famous stage of

sugarplum slumber that makes eyeballs go nuts, grants vivid visual dreams, and provided the

namesake for a certain famous rock band.

REM sleep is kinda paradoxical.

Your motor cortex is jumping all over the place, but your brainstem is blocking those

messages, leaving your muscles so relaxed that you’re basically paralyzed.

Except for your eyes.

That whole sleep cycle repeats itself every 90 minutes or so, transitioning back and forth

between the stages of sleep.

Obviously sleep is super important, and lack of sleep is terrible for your health, mental

ability, and mood.

In fact it’s a predictor for depression, and has been linked to things like weight

gain, as your hunger-arousing and -suppressing hormones get out of whack.

Sleep deprivation also causes immune system suppression, and slowed reaction time which

is why you should not drive sleepy.

Of course, a bad night’s sleep here and there is part of life, but there are a host

of bona fide sleep disorders out there that can really make life pretty terrible, or in

Mike Birbiglia’s case, land you in the emergency room.

We’ve got insomnia, which is persistent problems of falling or staying asleep.

And kind of its opposite, narcolepsy, whose sufferers sometimes experience brief, uncontrollable

attacks of overwhelming sleepiness, called “sleep attacks.”

This, as you can imagine, can get in the way of all sorts of things that you might enjoy

doing, like driving, eating, pole-vaulting.

Narcolepsy may have several different causes, including a deficiency in the neurotransmitter

hypocretin, which helps keep you awake.

But in more rare cases, brain trauma, infection, and disease may contribute to it as well.

So, that’s rare, but you probably know someone with sleep apnea, the disorder that causes

sleepers to temporarily stop breathing, until their decreased oxygen levels wake them up.

Birbiglia, meanwhile, turned out to have a REM sleep behavior disorder, which we don’t

fully understand yet, but appears to be associated with a dopamine deficiency.

Then we’ve got night terrors, which are as terrible as they sound...

spurring increased heart and breathing rates, screaming, and thrashing that’s seldom remembered

upon waking.

Night terrors are most common in children under seven, and may be spurred by stress,

fatigue, sleep deprivation, and sleeping in unfamiliar surroundings.

Much like sleepwalking and sleeptalking, night terrors occur during the NREM-3 stage of sleep,

and are NOT the same as nightmares, which occur, like most dreaming, during REM sleep.

But oh, in REM sleep, what dreams may come...

There you are, running naked as your teeth fall out, being chased down the beach by a

Matt Damon centaur.

You wake up, feel around your mouth thinking what?

What?

What?!

WHAT?!

Welcome to your dreams, those vivid, emotional images racing through your sleeping brain,

often providing a backdrop so bizarre that it may seem like David Lynch, Terry Gilliam,

and Tim Burton are trying to out-weird each other in a film festival.

A really, really long festival, considering the average person spends about six years

of their lives dreaming.

So yeah, sometimes you have really crazy dreams.

But mostly, your average dream usually just sort of unpacks and reshuffles what you did

that day.

For example last night I dreamt about Tumblr, cause I spent a lot of time on Tumblr yesterday.

If you played Tetris all afternoon, you might dream of blocks falling from the sky.

If something traumatic happened to you, your brain might provide you with a nightmare to

help extinguish your daytime fears - Thanks, brain!

Then again...you might be unable to stop dreaming about the trauma, which we’ll look at in

the future when we discuss post-traumatic stress disorder.

Our two-track minds of course allow us to register more stimuli than we outwardly acknowledge

during the day, and in that way, the sounds of car alarms or stinky dog farts that you

might not even have noticed may get incorporated into your dream, too.

And that’s all interesting and weird and sometimes a little gross, but what’s the

real purpose of dreaming?

Whyyy do we do this?

Well, as you might have guessed, there’s more than one idea out there…

The study of dreams is is a mix of neuroscience and psychology known as oneirology.

Oneiros is the Greek for dream, and if you’re a Neil Gaiman fan you may recognize it as

one of the Sandman’s many names.

The one that comes with a toga and Orpheus’s head.

But Sandman aside, if you want to talk dreams, we might want to start with our old friend

Freud.

In his landmark 1900 book The Interpretation of Dreams, Freud proposed that our dreams

offer us wish-fulfillment.

He thought a dream’s manifest content, the stuff you remember in the morning, was a sort

of censored and symbolic version of whatever inner conflict was really going on in that

dream’s unconscious, or latent, content.

Not surprisingly, the wish-fulfillment theory lacks scientific chops and has for the most

part fallen out of favor -- because, really, you can interpret a dream any way you want.

Like, sometimes a cigar is just a cigar.

Luckily we have some other theories to consider.

The information processing theory proposes that our dreams help us sort out and process

the day’s events and fix them into our memories.

This may be particularly important when it comes to learning and remembering new information,

and some studies show that people recall new tasks better after a good REM sleep full of

dreams.

But if brainwave readings show us anything, it’s that there’s a lot going on in your

brain when you dream, and the physiological function theory suggests that dreaming may

promote neural development and preserve neural pathways by providing the brain with stimulation.

When our brains are stimulated, they expand their connections more.

So, babies, for example, spend much of their sleep time dreaming, perhaps in part to help

their brain circuitry develop more quickly.

This is similar to the idea that dreams are part of our cognitive development.

By this model, dreams draw on our knowledge and understanding of the world, mimicking

reality, and engaging those same brain networks that light up when we daydream.

And finally, there are theories that focus on the way REM sleep triggers neural activity,

and the idea that dreams are just sort of accidental side-effects, the brain’s attempt

to weave a story out of a bunch of random sights, emotions, and memories -- which is

how in dreamland you might actually marry that Matt Damon centaur and give birth to

a baby with banana fingers and a raccoon tail.

For now scientists continue to debate the function of dreams, but one thing we know

for sure is that REM sleep is vital, both biologically and psychologically.

But, hey, you think your dreams are nut-bar?

Next week, we’re looking at other altered states of consciousness, where you’ll learn

what your brain really looks like on drugs, and whether you can actually hypnotize someone

to do your evil bidding… or just act like a chicken.

For now, if you’ve stayed awake during this episode, you learned about the four stages

of sleep -- NREM 1, 2, 3 and REM itself -- as well as some major theories for the psychological

purpose of dreaming, including information processing, physiological function, cognitive

development, and neural activity models.

Thanks for watching, especially to all of our Subbable subscribers, who make this whole

channel possible.

If you’d like to sponsor an episode of Crash Course, get a special Laptop Decal, or even

be animated into an upcoming episode, just go to Subbable.com/crashcourse.

This episode was written by Kathleen Yale, edited by Blake de Pastino, and our consultant

is Dr. Ranjit Bhagwat.

Our director and editor is Nicholas Jenkins, the script supervisor is Michael Aranda, who’s

also our sound designer, and the graphics team is Thought Café.